Delhi International Airport Ltd (DIAL) officials said during certification trials, the TaxiBots brought down the cost of fuel used during taxiing by 85%.

To curb air pollution and to help airlines save fuel, the Delhi airport operator is all set to buy TaxiBot – ‘pilot-controlled semi-robotic machines’ that tow aircraft from parking bays to the runway with their engine switched off, preventing any use of fuel.

TaxiBot has been an interesting program that has brought together leading edge automotive simulation, electronics, control technologies and special vehicle engineering skills to address one of the key environmental challenges facing the aerospace sector. It has set some industry firsts too, including the full dynamic modelling of an aircraft being towed under pilot control (using the ADAMS multibody dynamics and motion analysis software) and the physical demonstration of pilot controlled taxiing using the TaxiBot demonstrator vehicle and test trailer.

—Eric White, Ricardo chief engineer for TaxiBot

A study by IIT Kanpur says aircraft also contribute to air pollution.

The ignition will be turned on for take-off only when the aircraft reaches the runway starting point. These bots, the airport operator said, will be used only for departing flights.

Delhi International Airport Ltd (DIAL) officials said during certification trials, the TaxiBots brought down the cost of fuel used during taxiing by 85%.

A TaxiBot will be driven to an aircraft stationed at the apron area, preparing to take off. “The plane will then be attached to the TaxiBot. It will hold the aircraft’s nose wheel and lift it slightly. The plane’s pilot will then transport the aircraft from the terminal gate to the runway without switching the aircraft’s engine on. The engine will be turned on only a short while before the take-off to enable warm-ups and technical checks,” a DIAL officer said.

At present, the engines are switched on after passenger boarding is complete and remains on while taxiing until the aircraft reaches its designated runway. A TaxiBot can attain a maximum speed of 23 knots.

Once in use, the Delhi airport will benefit in many ways. “TaxiBot will reduce congestion at boarding gates. Carbon dioxide emission will drastically reduce along with other noxious gases. It will significantly reduce the risk of jet blast incidents at the apron area,” the officer said.

The airlines will save fuel and reduce damage to a plane’s brakes. “Whenever a plane applies brakes, the entire weight of the aircraft is on the nose wheel. The entire pressure will be now on the TaxiBots, leading to less damage, every time a pilot applies brakes,” the officer said.

A DIAL spokesperson said, “This initiative will significantly improve air quality at the airport and nearby areas. It will also help in reducing noise pollution and fuel consumption.”

A three-month trial of the TaxiBots will begin in September in association with KSU Aviation Pvt Ltd, which will provide the TaxiBots to DIAL. The TaxiBots have been developed by Israel Aerospace Industries (IAI).

The Directorate General of Civil Aviation, in its Aviation Environment circular 2013, had said aircraft taxiing was a major contributor in fuel burning and emissions at airports.

A study conducted by IIT Kanpur in 2016 on Delhi’s air pollution stated that at least two per cent of the city’s pollution (particularly No2 and PM2.5) comes from aircraft. A separate study by researchers from IIT Kanpur in 2011 said the IGI Airport emits around 1.18 million tons of CO2, 3,803 tons of NO2 and 2,900 tons of volatile organic compounds every year.

“Most of the emission from aircraft is during the LTO (landing and take-off) cycle, compared to time of flight within the Delhi border. Taxiing triggers a lot of pollution. If the authorities are using electric vehicles to tow the aircraft and the aircraft engines are shut down, it would significantly reduce the emissions,” said Mukesh Sharma, a professor of civil engineering at IIT Kanpur who led the study on pollution and its sources in Delhi.